The deal was expected to be formally announced by Sunday, but the Spain Under-23 international, who spent last season on loan at former club Espanyol, is now on his way back to San Siro.

"AC Milan announce that, due to a mild inflammation of the pelvic area, the player Didac Vila will return to Milan and rejoin the first team," a statement on the Italian outfit's official website read.

The collapse of the transfer is a major blow for Valencia, as they had identified Vila as the perfect replacement for rampaging left-back Jordi Alba, who completed a move to Barcelona in July.

The 23-year-old Vila arrived at Milan during the 2011 January transfer window, but made just one appearance in Serie A before being sent back to Catalunya on a temporary basis.